M9000 hydraulic fluid leaks from vent

[bsamot69]

A brief history, last year this tractor was leaking hydraulic fluid from the transmission vent on left side of tractor. The fluid was foamy with micro bubbles. Fixed the suction side defects, replaced filters and replaced fluid. For the most part of the past year the machine operated with no leaks. Now that I've been using the tractor more putting out hay in several pastures I have a hydraulic leak from transmission vent again. This fluid has no bubbles or foam, it's just fluid dripping out. The conditions that this occurs, driving loaded with two large round bales over 2 miles then back again for another load. I noted that it leaks after I start driving. If I am stationary loaded with the bales there is no leak. I drive to pasture pull up to gate, stop with tractor running to open gate, it is leaking pretty good. It stops if I let tractor sit for a minute idling with load. Noted that if fluid level is between the low mark and halfway up dipstick, I won't have any leak until the end of haying operation when I pull in facing downhill. (I check the fluid level whenthe tractor is cold, on level ground engine off)
I have checked all the vents. The vent on left top of trans is only place it leaks. I unplugged the right hand vent top of trans, it had dirt blocking it. Also checked the vent in back. So all vents open AND I took out dipstick and operated tractor. Same thing. It will leak only when driving down the road. Operating the rear implement and FEL while stationary does not have leak. The fluid leaking out is not bubbles/aerated. The fluid I have in it now is the fluid I used before all this leaking started when there was a suction side defects , sucking air into system. TRAVELLER'S I black bucket I believe. I did use a less expensive fluid during the repair stage but drained it out to put it in the current fluid. I think that is everything. What would cause this? Any ideas greatly appreciated

 

[PoTreeBoy]

A brief history, last year this tractor was leaking hydraulic fluid from the transmission vent on left side of tractor. The fluid was foamy with micro bubbles. Fixed the suction side defects, replaced filters and replaced fluid. For the most part of the past year the machine operated with no leaks. Now that I've been using the tractor more putting out hay in several pastures I have a hydraulic leak from transmission vent again. This fluid has no bubbles or foam, it's just fluid dripping out. The conditions that this occurs, driving loaded with two large round bales over 2 miles then back again for another load. I noted that it leaks after I start driving. If I am stationary loaded with the bales there is no leak. I drive to pasture pull up to gate, stop with tractor running to open gate, it is leaking pretty good. It stops if I let tractor sit for a minute idling with load. Noted that if fluid level is between the low mark and halfway up dipstick, I won't have any leak until the end of haying operation when I pull in facing downhill. (I check the fluid level whenthe tractor is cold, on level ground engine off)
I have checked all the vents. The vent on left top of trans is only place it leaks. I unplugged the right hand vent top of trans, it had dirt blocking it. Also checked the vent in back. So all vents open AND I took out dipstick and operated tractor. Same thing. It will leak only when driving down the road. Operating the rear implement and FEL while stationary does not have leak. The fluid leaking out is not bubbles/aerated. The fluid I have in it now is the fluid I used before all this leaking started when there was a suction side defects , sucking air into system. TRAVELLER'S I black bucket I believe. I did use a less expensive fluid during the repair stage but drained it out to put it in the current fluid. I think that is everything. What would cause this? Any ideas greatly appreciated

You might ask over at TractorByNet. There's a guy over there that has not 1 but 2 M9000's, and he'll let you know it.
It may just be the fluid swelling when it gets hot and agitated. Have you checked it when it's hot? The dealer warned my dad when he bought the Ford 3930 that it would weep out the transmission vent when it gets hot, and it does until it gets to the level it likes.

 

[JerryMT]

A brief history, last year this tractor was leaking hydraulic fluid from the transmission vent on left side of tractor. The fluid was foamy with micro bubbles. Fixed the suction side defects, replaced filters and replaced fluid. For the most part of the past year the machine operated with no leaks. Now that I've been using the tractor more putting out hay in several pastures I have a hydraulic leak from transmission vent again. This fluid has no bubbles or foam, it's just fluid dripping out. The conditions that this occurs, driving loaded with two large round bales over 2 miles then back again for another load. I noted that it leaks after I start driving. If I am stationary loaded with the bales there is no leak. I drive to pasture pull up to gate, stop with tractor running to open gate, it is leaking pretty good. It stops if I let tractor sit for a minute idling with load. Noted that if fluid level is between the low mark and halfway up dipstick, I won't have any leak until the end of haying operation when I pull in facing downhill. (I check the fluid level whenthe tractor is cold, on level ground engine off)
I have checked all the vents. The vent on left top of trans is only place it leaks. I unplugged the right hand vent top of trans, it had dirt blocking it. Also checked the vent in back. So all vents open AND I took out dipstick and operated tractor. Same thing. It will leak only when driving down the road. Operating the rear implement and FEL while stationary does not have leak. The fluid leaking out is not bubbles/aerated. The fluid I have in it now is the fluid I used before all this leaking started when there was a suction side defects , sucking air into system. TRAVELLER'S I black bucket I believe. I did use a less expensive fluid during the repair stage but drained it out to put it in the current fluid. I think that is everything. What would cause this? Any ideas greatly appreciated
[/Q
Let it sit overnight and drain some fluid from the drain plug to see of you have water there. Do this before you start it.

 

[Gb540]

Also have a M9000 that does similar. Doesn't foam, but it does burp/weep out the transmission vents. Not enough to drip, though it does attract dirt, which we just remember to clean off now and then.

Machine has done this for years with no other problems that we've seen.

 

[Captain13]

I saw you mentioned Traveler fluid in the original post. I had a Massey Ferguson a few years back and when I used Travelers in it, I would get a significant buildup at the vent. It was like the fluid was “cooking off” for lack of a better description. Almost like oil blow by from the crankcase on an older engine. I drained it and replaced it with Valvoline hydraulic fluid and the problem went away. As with any oil type vent (engine oil/hydraulic) there will almost always be a little dirty residue around the vent. If it’s not dripping, I wouldn’t be too concerned. My MF would even drip the Travelers fluid after a hard workout with harrows.

I only use Kubota hydraulic fluid in my M7040. Not a Kubota snob, but it is good hydraulic fluid. And yes it’s expensive.